The government has dropped plans to introduce controversial lie detector tests to catch benefit fraudsters after trials found that the technology is not sufficiently reliable.

The Department for Work and Pensions has given up on "voice risk analysis" (VRA) software after spending £2.16m on trials to assess whether the technology can identify people who are trying to fiddle the system when it eavesdrops on their telephone calls to benefit offices.

Plans to install lie detectors were hailed as a vote-winning move to get tough on benefit cheats when they were unveiled by the former prime minister, Gordon Brown, on the eve of the Queen's speech in December 2008. Ministers hoped the technology would make the benefits system more efficient and less costly.

VRA is meant to detect signs of stress in a caller's voice by analysing short snippets of speech, but critics say the system is not powerful enough to distinguish cheats from honest callers.

In 23 pilot studies, local authorities used the lie detector system to analyse phone calls from people applying for, or updating existing claims for housing benefit, council tax, income support and jobseeker's allowance. The technology was judged a success in only five of the trials.

A spokeswoman for the Department for Work and Pensions confirmed that the technology was being dropped now the trials had ended. "We have got the analysis back and have been going through whether it works when applied to the benefits system. This is the first time it has been used in the benefits system and the decision is that it is not very good value for money," she said.

The department organised two groups of trials. The first, in 2008, cost £460,000 and involved six local authorities and the department's executive agency, Jobcentre Plus. The second phase trial was expanded to 24 local authorities at a cost of £1.7m. Information from 45,000 calls was included in the evaluation, the department said.

Nine local authorities trialled the lie detector on calls about new benefit claims. Of these, only three said it worked well enough to highlight risky callers without raising too many false alarms. Of 12 local authorities who used VRA to spot cheats during benefit reviews, only one judged the trial to have been a success. Two local authorities tested VRA on callers who were reporting changes in their personal circumstances, with one reporting the trial as successful.

Voice risk analysis has been mired in controversy since scientists raised doubts over the technology soon after it reached the market. In 2007, two Swedish researchers, Anders Eriksson and Francisco Lacerda, published their own analysis of VRA in the International Journal of Speech Language and Law. They found no scientific evidence to support claims for the device made by the manufacturer, an Israeli company called Nemesysco.

Eriksson and Lacerda went on to say the software was "at the astrology end of the validity spectrum". Following complaints from Nemesysco's founder, the article was withdrawn from the website of the journal's publisher, Equinox Publishing and the authors were threatened with legal action by the company.

Professor Lacerda, who is head of phonetics at Stockholm University, told the Guardian he welcomed the government's decision to drop the technology.

"I praise the Department of Work and Pensions for the serious investigation they have done, which reinforces the strength of their decision. My only surprise is that it didn't come earlier. There is no basis for the device at all, so I would be surprised if they had reached another conclusion," he said.

"The problem with this device is that it is not even plausible to begin with. Had the department asked scientists in the UK they would probably have been advised not to bet on it, so this is a very expensive way of reaching an obvious conclusion," Lacerda added.

Under the "one strike and you're out" proposals put forward by Gordon Brown in 2008, people stood to lose their benefits for a month if caught out by lie detector tests. In a letter to Tracey Brown, director of Sense about Science, the minister for welfare reform, Lord Freud, confirmed that the department "has now discontinued interest in VRA".

Milan Vjestica, a consultant speaking for DigiLog, a Buckinghamshire-based company licensed to sell VRA in the UK, said: "The Department for Work and Pensions have not said that it doesn't work. They have said that local authorities can, as part of their own fraud and error strategies, use VRA amongst other tools.

"The concerns that some scientists have raised have been strongly contested by Nemesysco. This was one example of scientists saying in their opinion it didn't work. It's not like there is a whole host of people saying it doesn't work."